Historic, archived document
Do not assume content reflects current
scientific knowledge, policies, or practices.
UNITED STATES DEPARTMENT OF AGRICULTURE
Agricultural Research Administration
Bureau of Agricultural and Industrial Chemistry
H CHEMICAL CHANGES IN STORED GRAINS ,
, A Selected and Annotated
Bibli ogr aphyl/ ^
1. Babbitt, J. D. Hysteresis in the adsorption of water vapor by wheat.
Nature 156: 265-266. 1945.
It is not possible to bring dried wheat back to its original wet
moisture content, because of hysteresis.
2# & The thermal properties of wheat in bulk. Canad. 'jour.
Res. Sect. F., 23 (6): 388-401. 1945.
3. Bakke, A. 0., and Stiles, H. Thermal conductivity of stored oats
with different moisture content. Plant Physiol. 10: 521. 1935.
4. Barton-Wright, E. C, and Tompkins, R. G. The moisture content and
growth of mold in flour, bran, and middlings. Cereal Chem.
17: 332. 1940.
5. Blanc, A. Essais de conservation de ble in atmosphere confine e.
Compte rendues des seances de l'Academie d' Agriculture de. France
24 (18) : Supplement a la seance du 8 juin 1938. '
6. Carter, Edward P., and Young, George Y. Effect of moisture content,
temperature, and length of storage in the development of "sick"
_wheat in sealed containers. Cereal . Chem. 22: 418-428. 1945.
"'Sick' wheat was produced artificially .by storing sound wheat
containing different amounts of moisture in sealed quart Mason jars
at various temperatures in temperature-controlled cabinets, the pro-
portion of «sick» kernels in general increasing with the moisture
content of the grain, the temperature of storage, and the length of
p the storage period. There was little fungus growth on the wheat
1/ This is an interim, non-exhaustive addition to the bibliography on
Chemical Changes in Stored Grains, processed publication by
Carol M. Jaeger, Northern Regional Research Laboratory, Bureau of
Agricultural and Industrial Chemistry, Agricultural Research Adminis-
tration,^. S. Department of Agriculture, March 1943 i
- 2 -
such as usually takes place when moist wheat is exposed in the open
air, except in a few jars and these were discarded*
"Itfheat containing 12.2 percent moisture stored at 40° C. developed
'sick' wheat symptoms when stored 279 days or longer, but not when
stored at a lower temperature. A small percentage of 'sick 1 wheat
was produced in 32 days in wheat containing 18.6 percent moisture
when stored at 5° C. and up to 100 percent 'sick 1 kernels when stored
at higher temperatures and for longer periods of time . The develop-
ment of the 'sick' wheat condition in general was accompanied by
loss in viability and increase in fat acidity."
7. Christenson, Clyde M., and Gordon, Dorothy R, The mold flora of
stored \vheat and corn and its relation to heating of moist grain.
Cereal Chem. 25: 40-51. 194-8.
"••••The number of molds on corn increased with increasing
moisture content of the seed, •• ••Auto clave d moist wheat inoculated
with 200,000 spores of Aspergillus flavus per gram heated to 45° C»
in 2 days, while that inoculated with only 0.2 spore per gram heated
to a comparable temperature in 9 days, indicating that if conditions
for mold growth. are favorable, the amount of inoculum originally
present may have only a minor effect on eventual heating. Under
conditions of the tests, none of the several fungacides used elim-
inated molds from moist, stored wheat, and thiourea appeared to be
less toxic to A. candidus than to other common molds."
8. DeLong, H. H. Safe storage for grain sorghums, S. Dak. Agr. Eng #
Pamphlet No* 3 (Rev.) Aug. 1945.
Progress report on the six methods of sorghum grain storage noi?
being investigated at South Dakota, (Nothing on chemical changos.)
9» Dexter, S. T., and Croighton, J, W, A method for curing farm prod-
ucts by the use of drying agents • Jour # Amer. Soc. Agron.
40 (1): 70-79. 1948.
"Blocks of wood or other porous material impregnated with a
suitable proportion of calcium chloride, magnesium chloride, or other
desiccant have been found effective in removing moisture from the
interstitial atmosphere, and thus from hay or grain in mows or bins.
With this method of reducing the relative humidity in the storage
space, spoilage was prevented. Blocks may be so prepared that they
will readily absorb from 50 to 100 percent or more of their dry
10. Hutchinson, J. B., and Booth, R. G. The drying of wheat. IV Phos-
phatase activity as an index of heat damage in cereals. Jour, Soc,
Chem, Indus. Trans, 65 (8): 236-237. 1946.
- 3 -
"The baking quality, germination vitality, and phosphatase
activity of a wheat were examined aftor heat treatment at moisture
contents ranging from 5.5 to 35 percent. Curves relating the per-
centage of phosphatase inactivation to temperature of treatment are
presented. The correlation between phosphatase inactivation and
damage to either vitality or baking quality varies with moisturo
content and is less than that between vitality and baking quality
in the important region above 15 percent moisture. The detection
'and use of an enzyme system of greater heat lability than phosphatase
is desirable for the unequivocal diagnosis of mold damago to either
vitality or baking quality of wheat*"
*^ # —_—_——. teeer, E. N., and Thomas, P. T# Heat damage in cereal
grains. Nature 158 (4-004): 120-121. 194-6.
A cytological study, mainly, and a comparison with burn damago
of animal tissues.
12. James, Norman, Wilson, Joyce, and Stark, Egon, The microflora of
stored wheat. Canad, Jour, Res,, Sect, C, 24- (5): 224-233. 194-6.
Wheat passing through the Winnipeg market in 1943 and 194-5
harbour od a large number of microorganisms. It is suggested that
these species should be considered epiphytic on wheat.
13» Karon, M. L., and Altschul, A. M. Respiration of cottonseed. Plant
Physiol, 21 (4): 506-521. 1946. ■
14. Kretovich, V, L# Physiologico-biochemical bases for the storage of
grain, Akad, Nauk. U,.S, S. R,, Inst, Biokhim,, Moscow-Leningrad.
1945, 136 pp, (Separate); translation at USDA Library, Washington,
D. C, Chem, Abs, 40 (5): 1237 8 . 1946.
Many analyses are given showing the biochemistry of grain ripen-
ing, and summaries of experiments are given' on the most beneficial
ways of treating wheat for storage.
15. Kyame, Lillian, and Altschul, A, M. Comparison of respiration, free
fatty acid formation, and changes in the spectrum of the seed oil
during the storage of cottonseed. Plant Physiol, 21 (4): 550-561, 1946
"That both respiration and lipo lysis equally reflect the vigor of
cotton seeds is a fact of great practical importance in commercial
storage. On the basis of this fact it would be reasonable to predict
that, seeds whose respiration intensity is high — that is, seeds that
heat readily when stored in bulk would, even when heating is controlled
by air circulation*, .undergo more intensive lipolysis than seeds of
equal moisture content but lower respiratory activity. Thus, the
measurement of the heat resulting from respiration should be a useful
criterion in predicting the storage behavior of seeds.
_ 4 -
"The behavior of immature seeds is entirely different from that
exhibited by mature, seeds. In immature seeds, the enzyme systems
have not reached the state of dormancy which characterizes them in
mature seeds. For- this reason, immature, seeds are more sensitive
to moisture and respire at a higher intensity than do mature seeds.
• ..•In effect, then, the maturation process which is interrupted by
early harvesting of the cotton, is continued during storage."
16. Lewis, S» E., and Eccleston, K» Residues in wheat flour fumigated
with methyl bromide. Jour. Soc. Chem. Indus. 65 (5): 149-152. 1946.
17. Longwell, J. H. Effect of storage on the feed value of hard red spring
wheat. N. Dak. Bimonthly Bui. v. 7, No. 6, pp. 3-6. 1945.
Wheat from the 194-0 crpp was placed in the Commodity Credit
Corporation storage bins in the summer of 1941 • Examination of the
wheat in the spring of 1944 gave the following results: (a) There
were differences in moisture, test-weight, total nitrogen, and
germination; and (b) no differences in feeding value for fattening
pigs were found. t
18. McCalla, A. G., and Newton, Yf. Effect of frost on wheat at progressive
stages of maturity. II Composition and biochemical properties of
grain and flour. Canad. Jour. Res., Sect. C, 13 (1): 1-31 • 1935.
III Milling and baking quality. Ibid Sect. C, 13 (5): 263-282. 1935.
19. Milner, Max, and Geddes, 17. F. Grain storage studies. I Influence
of localized heating of soybeans on interseed air movements.
Cereal Chem. 22: 477-483. 1945; II The effect of aeration, temper-
ature, and time on the respiration of soybeans containing excessive
moisture. Cereal Chem. 22:: 484-501.. 1945; III The relation between
moisture content, mold growth, and respiration of soybeans. Cereal
Chem. 23: 225-247. .1946. . .
20. Utility of sulfa drugs for the inhibition of mold respira-
tion in grain. Science 104 (2707): 463-464. 1946. . .-...
"It is significant that the respiratory rate of the control sample
on the first day, before mold proliferation commenced, was the same
as that of samples treated with sulfanilamide. This respiratory
rate (about 33 rag. CO2/IOO g. dry matter/day) remained virtually
constant for 8 days at the highest concentration of sulfanilamide
and is probably representative of the true seed respiration under the
conditions of moisture and temperature applied. Germination data
indicate that suppression of mold growth by sulfanilamide yielded
a larger percentage of viable seeds at the end of the trial."
21. Christensen, Clyde M., and Geddes, W, F. Grain storage
studies. V Chemical and microbiological studies on "sick" wheat.
Cereal Chem. 24 (1): 23-38. 1947.
- 5 -
The effects of molds and bacteria on wheats and relation to "sick"
wheat are discussed. In addition to kernel studies, work on milled
samples gave the f o 11 owing results:
"Fat acidity of mill fractions of sound wheat was at a maximum
* • ' in the bran fraction, and decreased regularly toward the patent flour
more or less in the order of the total fat content of the various"
fractions. The mill fractions of •sick 1 wheat, on the other hand,
showed highest fat acidity in the low-grade flour. The high lipase
activity of the aleurone layer and scutellum, relative to that of
the germ, is apparently responsible for this effect,
"More information is needed on the location, distribution, and
activity of inherent wheat enzymes, such as the lipases and oxidizing
enzymes, to explain the formation of fat acidity and the darkening
of 'sick' wheat,"
22 • • Christenson, Clyde M., and Geddos, 17. F, Grain storage
studios', VI wheat respiration in relation to moisture content,
mold growth, chemical deterioration, and heating. Cereal Chem.
24 (3): 182-199. 1947.
*&• , Christenson, Clyde M., and Geddes, 17, F, Grain storage
studies. VII Influence of certain mold inhibitors on respiration
of moist wheat. Cereal Chem. 24 (6): 507-517. 1947.
"More than 100 compounds were tested for fungistatic ability on
wheat stored with a moisture content of 16 to 25 percent. Few of
these effectively inhibited the growth of molds on or in the seed.
Some compounds inhibited certain molds but not others, or inhibited
the surface growth and spore production of certain molds without
preventing the growth of the molds in the interior of the seed. This
suggests that the effectiveness of the given compound in inhibiting
the development of molds on or in moist stored seed of any kind can
bo ascertained only by determining the number and kinds of molds
originally present, and their subsequent increase or decrease after
the seed has been treated with the supposed fungicide, ,,.,"
24. Morey, Loran, Kilmer, Helen, and Selman, Roland W; Relationship
between moisture content of flour and humidity of air. Cereal
Chem. 24 (5): 364-371. 1947.
"The equilibrium moisture contents of a typical Kansas flour in
contact with air of varying moisture content at 50°, 75°, and 95° C.
were determined. A linear relationship exists between flour moisture
content and the absolute humidity of the air. For a moisture content
of 14 percent, the reciprocal of the absolute temperature is a linear
function of the logarithm of the water vapor pressure. The heat of
dehydration has been calculated as 10,7 calories per mole of water,"
- 6 -
25. Nagel, C. M., and Semeniuk, G. Some mold-induced changes in shelled
corn. Plant Physiol. 22 (1): 20-33. 1947.
"Shelled corn which molded during storage was found to be high
in fat acidity and moisture percentage and low in bushel weight • •••
"Pure cultures of nine fungi isolated from naturally molded
corn were grown- in the laboratory for a 4-week period on steam-
sterilized corn initially adjusted to approximately 32 percentage
moisture content .«««
"A positive linear relationship was found between the percentage
loss in organic matter and the percentage of water (wet basis) in
the moldy corn .«©
"Fat acidities in the corn were increased by all the fungi tested
in this series- of • experiment So .00"
26. Robertson, Do W*, Lute, A,o;II*, and Kroeger, K. Germination of 20-
year old wheat , oats, barley, corn, rye, sorghum, and soybeans*
Jour* Amer, Soc. Agron,., 35 (9): 786-795. 1943o
"Germination studies are reported on various farm crops stored
for varying per. teds from 1 to 22 years - n a « A dry, arid climate pre-
serves germination in the farm crops studies so that stock of wheat,
oats, barley, sorghum, and cum can be stored for 20 years and still
have enough viable seeds to maintain the stocks c "
27. Sayro, J< D ff Storage tests with seed corn. Farm and Home Research
(Bimonthly Bui.) Ohio Agr, Expt. St a. 32 (247): 149-154. 1947.
"Seed corn can be carried over for a number of years by drying it
to 5 to 8 percent moisture content and storing it in air-tight con-
tainers at a low temperature, if possible, or in as low and as uni-
form a temperature as is available ."
28. Scherwood, R. C. The influence of drying on quality of wheat. Min.
Dept. of Agr, Bui. 66. 1929*
29. Schulerud, A. A study of the march of acidity in stored flours and
some critical remarks on the methods used for the determination
of flour acidity. Cereal Chem, 10 (2): 129-139. 1933.
30. Sharp, P. F,, and Elmer, R, YJheat and flour studies. I Proteolytic
enzymes of flour© I Auto -digestion of flour milled from frozen and
non-frozen wheat harvested at various stages of maturity. Cereal
Chcm. 1 (2): 83-106 • 1924.
- 7 -
"Protein fraction analysis of flour mi Hod from wheat harvested .
.at various, stages of growth, as described, indicates no change in *
the glutenin, an increase in the gliadin, •and a' decrease in the 5
percent potassium sulphate -soluble and amino nitrogen as the kernel
"Subjection of the immature wheat to freezing temperatures by the
method described had no effect -on the protein fractions 'as compared
with the- non-frozen vj-ho at # »'
"The total protein of the flour milled from wheat harvested at
various stages of maturity did not differ greatly although a slight
decrease followed by an increase is indicated over the .range studied.
"The proteolytic enzymes of wheat flour are capable of digesting
the flour protein if given sufficient time in which to act.
"Auto-digestion of flour for a considerable period of time apparently
produces no decrease in the glutenin, causes- a decrease in the gliadin,
and an, increase in the 5 percent potassium sulphate -soluble and amino
nitrogen fractions'. The decrease in the gliadin fraction is not all
accounted for by the increase 'in the potassium sulphate-soluble fraction
but also shows up as an 1 increase in the glutenin fraction.
„ ... .! l The decrease in the -gliadin fraction is apparently independent
of the stage of kernel development, but the percentage increase in the
potassium sulphate -soluble fraction is greater in the more immature
stages of growth.
"Freezing as carried out under these conditions apparently affects
the proteolytic activity of the flours very little if at ail*!'
31. __________ Wheat and flour studies*- III The amino nitrogen content
on the immature wheat kernel and the effect of freezing. Cereal
Chem. 2 (1): 12-38* 1925 J * VII The composition -of wheat "and mill
, products from frozen and non-frozen wheat harvested at various
stages of maturity. Cereal Chem* 3 (6) 9 402-410, - 1926r.
32. Simons, J. W. 'Drying seed grain with calcium chloride.- Agr. Engin,
29 (3): 112-113. 1948.
Gives data on drying blue lupine seeds.
33. Smith, Luther. The effect of chaff of oereals en germination of
v -y.seeds and on the growth of mold-. Jour. Amer. Soc. Agron.
40. 1.1): 32-44. 1948. •• ■ '. " '
34. Sreenivasan, A. Storage changes in rice after harvest. Indian Jour.
Agr. Sci. 9 (Pt. 2): 208. 1939; Biochem. Zschr. 301: 210. 1939.
- 9 -
tfWith the natural moisture of approximately 13,5 percent the seed
was dead after 5 months' storage at 30° C.'and after 2 years at 20° •
Full viability was kept for 3 years at 10°, but germination foil
rapidly after that. Practically full germination was maintained for
10 years at 2° and full germination at -10°.
"Seed dried to 8 to 9 percent moisture showed little or no loss of
germination when stored at 30° C. for 1 year, but the fall in germi-
nation was very rapid after 1 year, Soed stored at 20° germinated
90 percent after 5 years and lost viability gradually in subsequent
years. The seed stored at 10°, 2°, and -10° did not change in
germination in 10 years.
"Seed dried from approximately 13.5 to approximately 5 percent in
44 hours showed severe injury to germination when stored at low-
38. Whymper, R., and Bradley, A. A note on tho viability of wheat seods.
Cereal Chem. 24 (3): 228-229. 1947.
The authors report a viability of 69 percent after 32 years of
storage for some English wheats*
39. Winteringham, F. P. TIT., and Harrison, A. The sorption of methyl
bromide by whole wheat. Jour. Soc. Chem. Indus, 65 (5): 140-149.